This invention relates generally to downhole tools joined in a tool string and forming a downhole telemetry network. These tools often have components that are displaced in rotation and translation during use. More particularly, this invention relates to downhole tools comprising transmission rings connected by an extensible transmission line that permits signal transmission during the operation of the tool.
Real time telemetry via a downhole network has long been desired by the oil, gas, and geothermal well drilling industries. Although there is much literature on the subject, until now, a commercial system offering real time high-speed data rates has not been available. This invention is an application of the first successfully demonstrated downhole high-speed telemetry network. This enabling technology allows real-time bidirectional telemetry all along the drill string between the drill bit and the surface. The investigator is directed to the applicants' U.S. Pat. No. 6,392,317, pending U.S. Application 20020075114A1, and pending PCT application WO2001US0022542, incorporated herein by this reference, for further details concerning the nature and application of the invention.
This invention pertains to drilling tools that undergo rotational or extensional cycling, either continuously or on demand in the drilling operation. A modern drill string, or tool string, is made up of many different tools. Some of them are passive, while others are active, performing drilling functions in addition to providing a torque connection between the drill bit and the surface platform. The objective of this invention is to provide a means for accommodating the cycling of such tools while enabling transmission of data along the string. Examples of tools that undergo rotational or extensional cycling, either continuously or on demand in the tool string are found in the following U.S. Patents.
U.S. Pat. No. 6,481,495, to Evans, discloses a downhole tool known as a hydraulic drilling Jar. It teaches the use of a telescoping mandrel positioned in the housing of the tool. The mandrel provides an annulus housing the active components of the tool. The tool also provides for a conductor member positioned in association with the mandrel for transmitting an electronic signal through the tool. The conductor is insulated from the conductive drilling fluid by means of a sealed chamber filled with a non-conductive fluid. The disclosure goes on to teach that the conductor is designed to elongate as the tool cycles. The means for providing elongation of the conductor is supplied forming the conductor cable into a helix. This disclosure relies on a variety of direct contact components to complete the electrical path through the tool.
U.S. Pat. No. 5,396,965, to Hall et al., one of the inventors herein, discloses a downhole hammer for use in a drill string. The abstract of the invention discloses the general nature of the hammer and its use downhole. According to its broadest aspect, the invention is a down-hole mud actuated hammer for use in a drill string, which includes a housing with an upper end having means for connecting to the drill string. A throat is located within the housing, which throat includes a main flow passage to allow high pressure drilling mud to pass there through. A piston is provided which is adapted to move axially within the housing means to reciprocate between an up position and a down position. The piston is moved between the up and down position by a minor portion of the high pressure mud, which portion passes from the main flow passage into at least one piston actuating chamber. This minor portion of mud is exhausted from the piston actuating chamber to a low pressure region out of the housing without being returned to the main flow passage. The present invention teaches how this tool may be adapted for inclusion in a downhole network.
U.S. Pat. No. 6,308,940, to Anderson, discloses a downhole shock absorber for use in a drill string. The tool employs both rotationally and translationally actuated components to dampen the drill string vibrations present in drilling deep wells. The tool comprises multiple segments that are threadably connected together to provide a tool compatible with standard drill string components and makeup. The assembly allows for longitudinal telescoping movement of the active components of the tool which are housed in an annulus that is defined by an axial flow passage and by the tool's housing. The flow passageway permits the circulation of drilling fluid through the tool and the tool's housing. The operation of the tool is described as follows. If the shock wave impinges on the tool, a mandrel telescopes into the drive cylinder. This allows continued rotational movement while simultaneously absorbing, by both mechanical and hydraulic means, the energy of the shock. The shock is dampened by the movement of the mandrel into the annular space provided by the drive cylinder, connector sub and compression cylinder. The present invention teaches how this tool may be adapted for inclusion in a downhole network.
This invention, therefore, provides a means for adapting downhole tools that undergo rotational or translational cycling for inclusion in a high-speed telemetry network down hole. Real time data may then be transmitted to and from the drill bit and other sensors and equipment along the drill string.